<div xml:space="preserve">
  
<p>Author: Robert S.</p>
  
<p>This command calculates the area of arcs, circles, ellipses and elliptical
arcs, and optionally adds the information to the current layer of a drawing.
If you select any other type of entity a warning is shown in the command
line.</p>
  
<p>For arcs, there are two options for calculating areas, namely Segment or
Sector. The area of a segment (or slice) is the area bound by the arc and two
lines drawn from the arc's startpoint and endpoint to the arc's centre. The
area of a sector is the area bound by the arc and a chord drawn from the
arc's startpoint to the endpoint.</p>
  
<p><img alt="Segment or Sector" src="ArcCircle01.png" />
<br />Figure 1: a segment (slice) and sector.</p>
  
<p><b>Options</b></p>
  
<p>This command has the standard "<i>Add measurement to drawing</i>" and 
"<i>Text Height</i>" options.</p>
  
<p><img alt="Standard options" src="ArcCircle02a.png" />
<br />Figure 2: Standard Info options</p>
  
<p>Whether this is off or not, when you click on an arc, circle, ellipse or
  elliptical arc, the information is displayed in the command line widget.</p>
  
<p><img alt="Info is displayed in command line widget" src="ArcCircle03.png" />
<br />Figure 3: Info displayed in command line</p>
  
<p>(Note: Every time you start an info command the "<i>Add measurement to drawing</i>"
checkbox is always unchecked. You must remember to switch it on if you want the info 
added to the drawing).</p>
  
<p>It also adds the following options.</p>
  
<p><img alt="Options toolbar" src="ArcCircle02.png" />
<br />Figure 4: Added options</p>
  
<p><b>Mode:</b></p>
  
<p>The mode only applies to arcs.</p>
  
<p><img alt="Sector" src="InfoSector.png" height="24" width="24" />
<br /><i>Sector:</i> This mode returns the area of the sector. This is useful when
used in conjunction with the "<i>Polygonal Area</i>" command.</p>
  
<p><img alt="Segment" src="InfoSlice.png" height="24" width="24" />
<i>Segment:</i> This mode returns the area of the segment.</p>
  
<p><b>Add:</b></p>
  
<p><i>Entity:</i> This selects whether you want to add a copy of the measured
entity to the current layer of the drawing.</p>
  
<p><i>Chord:</i> This selects if you want the chord (sector), or radius lines
(segment), added to the drawing.</p>
  
<p><i>Length:</i> By default the area is always printed on the drawing. This
option selects whether you want extra information added to the drawing.</p>
  
<p>For circles and full ellipses the extra information is the circumference.
This uses the centre point as the lower left corner for the added text.</p>
  
<p><img alt="Extra info for circles and ellipses" src="ArcCircle04.png" /></p>
  
<p>For circular arcs the extra information is the length of the arc and the
length of the chord (in sector mode), or the radius (in segment mode).</p>
  
<p>For ellipses the extra information is the length of the arc and the length
of the chord (in sector mode), or the distance from the centre point to the
startpoint of the arc, followed by the distance from the centre point to the
endpoint of the arc (in segment mode).</p>
  
<p>The lower left corner for the added text is the endpoint of the arc.</p>
  
<p><img alt="Extra info for arcs" src="ArcCircle06.png" /></p> 

<p><img alt="Extra info for arcs" src="ArcCircle05.png" /></p>
  
<p><img alt="Extra info for arcs" src="ArcCircle08.png" /></p>
  
<p><img alt="Extra info for arcs" src="ArcCircle07.png" /></p>

</div>
